Routing Internal Application Emails to CES

[sfrancis]

We have many internal applications that need to route mail via SMTP from onprem network to our CES instance. When testing a script to inject a send-mailmessage we define the $To, $From, $Subject, $SMTP.  The mail messages are getting blocked because the CES instance sees it coming from a 10. IP address. Is there an easy way to configure this? 

[Vinay babu]

As the CES is cloud deployment. The Public NAT IPs of your onprem applications needs to be allowed at CES to relay the emails.

Usually, if the recipient is internal domain user, then the application directly sends to your Exchange/O365 server and if the recipient is external then the application sends to CES to deliver to the external email server. Thanks.